The prior art of removal of paint, putty and the like from a work surface has, historically, consisted of various types of scraping means, as is reflected in U.S. Pat. No. 3,028,152 (1962) to Scholl, entitled Resurfacing Tool, U.S. Pat. No. 3,613,147 (1971) to Norfleet, entitled Wall Surface Scraper Tool and, secondarily, such patents as U.S. Pat. No. 3,604,520 (1971) to Shato, entitled Sonically Driven Paint Scraper; U.S. Pat. No. 3,722,022 (1973) to Falleson, entitled Rotating Paint Scraper; U.S. Pat. No. 3,731,338 (1973) to Walsh, entitled Mechanical Paint Scraper; U.S. Pat. No. 4,554,957 (1985) to Zayat, entitled Rotary Resurfacing Tool; U.S. Pat. No. 4,559,661 (1985) to Tsais, entitled Paint Scraper; and U.S. Pat. No. 4,485,349 (1989) to Demetrius, entitled Sander Paint Scraper.
For purposes of the present application, the most applicable references comprise said U.S. patents to Scholl and Norfleet. By way of illustration, salient portions of the structure of Norfleet are shown in FIGS. 1 and 2 herewith. It may therein be appreciated that the structure of Scholl is one intended for the treatment of delicate flat surfaces such as work surface 20 in which all paint and the like have already been removed. As such, Scholl is not designed for heavy duty abrading of old paint and putty, as is the inventive structure set forth herein. This primarily due to the fact that cutter blades 54 of Scholl are pivotally mounted upon pivot points 55, the purpose of which is to enable blades 54 of Scholl to rotate off of the work surface if they encounter excessive resistance there from. As such, it is to be appreciated that Scholl is intended as a planning or refinishing tool to create smooth surfaces that are then ready for refinishing, not to effect removal of layers of hardened old paint. As such, Scholl may be understood as a low power, low rpm device, while the within system is that of a high power, high rpm device.
Further, Scholl, to control depth of the cut, uses a system of rings 56 (see FIG. 1). The effect of which is to produce a marginal, i.e., less than two percent, change in the angle of the plane of rotation of cutting assembly 57 thereof. In addition, Scholl does not employ any form of buffering means between cutting elements 54 and the work surface 20. Accordingly, other than the location of edge 58 of the structure of Scholl, there exists no mean of control, during the operation Scholl, of the interface between the cutting assembly and the work surface 20. In addition, the structure of Scholl is unable to provide a scraping, abrading or cutting function to an integral secondary surface such as transverse surface 42 which is shown in FIG. 1, this due to the fact that the cutting assembly 57 of Scholl is entirely enclosed within the peripheral ring structure 56 thereof. As such, no form of cutting outside of the periphery of ring structure 56 is possible.
With regard to the structure of Norfleet, the same is generally shown in the view of FIG. 3. Therefrom, it may be appreciated that the only form of control of depth that exists lies in the use of rollers 59 and slidable adjustment of the depth of cutting elements 60 thereof. As such, it is necessary to manually adjust each of these cutting elements (typically four in number) in order to adjust the depth of the cut relative to primary work surface 20. Apart from the above, the Norfleet gives rise to safety issues in that no housing or shroud exists about cutting assembly 61 thereof, such that material removed from the surface 20 will be uncontrollably ejected from the work surface, thereby generating hazardous dust and debris in the work area. Further, Norfleet, like Scholl, does not include any capability for simultaneously removing paint, putty and the like from an integral transverse secondary surface such as surface 42. In fact, due to the offset from cutting element 60 created by rollers 59, it is unlikely that the structure of Norfleet could effect any removal of material from the secondary surface 42.
In general terms, much of the offset prior art suffers from a lack of effectiveness in the desired function of paint removal as, particularly, is the case with sonically operated devices such as Sheeto.
Those paint removal devices of the rotating type are generally unacceptable for use upon any fine or quality work surface in that they create excessive gouging during the process of paint removal. In other words, in such devices, although the paint may be removed, the underlying work surface is so damaged that a repair of that surface is necessary before any painting can begin.
Other paint removal devices comprise in effect glorified sanding machines and, as such, make no contribution to the art of tools for paint removal. That is, sanding devices, when used for the purpose of paint removal, are only able to remove paint in a uniform fashion to a certain depth. Also, damage to the underlying wood, beneath the paint, is generally inevitable as is the creation of ridges within the wood caused by the edges of the reciprocating sanding tool. Other devices, such as that reflected in Zayat above, have application only to work surfaces of a particular geometry, e.g., shingles or clap boards in the case of Zayat.
There has accordingly long existed a need in the art for a power tool useful in the removal of paint from a work surface that will not damage the work surface, will function efficiently, is applicable to a variety of pipes and thicknesses of paint, and which can be integrated with state of the art vacuum debris removal means which are now an OSHA requirement with many industrial power tools.
The instant invention may therefore be viewed, as a response to the above long-felt need in the art.
The present tool for the removal of paint and putty includes a semi-circular assembly housing including a semi-circular rigid collar secured thereto. The tool also includes a disk-like abrading assembly rotatably and co-axially mounted within said semi-circular collar of said housing, said assembly including rigidly disposed abrading elements projecting both axially and radially therefrom, said assembly defining a plane of rotation. The inventive tool further includes a motor for high-speed rotation of said assembly, said motor located externally of said housing. The present tool also includes bearing means for establishing a fixed axial cutting depth relative to a primary work surface positioned thereagainst, in which the bearing means function as a buffer between said abrading assembly and said work surface to thereby improve control and mobility of said assembly relative to the primary work surface. A platform is disposed between said assembly housing and said motor, in which said platform is preferably co-planer with said plane of rotation of the abrading assembly. Said platform is rigidly secured to said motor. The inventive tool yet further includes means for tilting said assembly housing relative to said platform to thereby expose a greater area of said abrading assembly to increase depth of cutting in an axial direction upon the primary work surface at that side of said abrading assembly which is tilted thereby. The instant tool yet further includes means for selectably increasing the effective polar dimension of said semi-circular assembly housing to correspondingly decrease radial projection of radial cutting surface of said abrading element relative to a virtual circumference defined by an open polar segment of the semi-circular assembly housing.
It is accordingly an object of the invention to provide a power tool for the efficient removal of paint and putty from integral transverse work surfaces.
It is another object to provide a tool of the above type capable of removing paint from work surfaces without damage to the wood or other material beneath the paint thereon.
It is a further object of the invention to provide a tool of the above type in which the degree of abrasion or cutting of the paint upon the work surface can be regulated through control of both the axial position of the abrading elements and of a buffer means surrounding the same.
The above and yet other objects and advantages of the present invention will become apparent from the hereinafter set forth Brief Description of the Drawings, Detailed Description of the Invention and Claims appended herewith.